detroit is the largest city in the u.s. to declare bankruptcy in the red more than $18 billion. other even larger cities could be next. in a little more than three months, new yorkers will elect a new mayor. in a recent warning from mayor michael bloomberg to his successor is now reverberating around the city. >> avoiding the hard choices is how detroit went bankrupt. >> reporter: bloomberg says health and pension costs for city work that's right contributed to detroit's financial ruin threaten economic stability. most new york city employees and retirees pay nothing for $6.3 billion in health insurance. workers also pay little for tensi pensions that have taxpayers on the hook for $8 billion this year. >> new york city has right now 10,000 police officers retired who are under 40 and collecting pensions and they will technically collect those pensions for the rest of their lives. >> reporter: contracts for almost all 300,000 city workers expired at least three years ago. the next mayor will be under pressure to win concessions. >> the unions have tried to wait it out. they don'